Fig. 2.

Distinct features of pediatric physiology that may contribute to the unique fibrosis pattern and progression seen in children. The process of neonatal or pediatric liver fibrosis differs from that in adults. Neonatal liver clearly lacks the mature architecture and enzyme levels. Similarly, cholangiocytes have immature barrier mechanisms that protect them from bile flow. Interestingly, the neonatal liver has a robust fibrogenic environment despite higher regenerative potential of the skin. The neonatal immune system is immature. CD8 T cells tend to differentiate into effector cells, while the hepatic immune system significantly differs in functionality and composition. The pediatric microbiome shifts across ages and impacts many disorders. CYP450, cytochromes P450; α-SMA, α-smooth muscle actin; Th, T helper; KC, Kupffer cell.